A Peak-to-Average Ratio (PAR) or crest factor of a signal is a ratio between an average level of the signal and a maximum magnitude of the signal. FIG. 1 illustrates an example of a transmission signal in a wireless communication system. A signal s(t) on a time axis is shown in FIG. 1. The PAR or the crest factor implies a ratio of a maximum value 110 against an average level of the s(t). In general, the crest factor may be calculated in a dB scale. Therefore, the PAR or the crest factor may be given in a logarithm form of a ratio between an average signal level and a peak.
If the signal has a high PAR, a high power amplifier is required which operates with large input back-off. Accordingly, amplification of the signal having the high PAR is not effective in general. Therefore, there is a need to propose an effective alternative for reducing the PAR.